U.S. patent number 10,548,215 [Application Number 16/124,896] was granted by the patent office on 2020-01-28 for flexible printed circuit, method for fabricating the same, and display device.
This patent grant is currently assigned to Beijing BOE Display Technology Co., Ltd., BOE Technology Group Co., Ltd.. The grantee listed for this patent is Beijing BOE Display Technology Co., Ltd., BOE Technology Group Co., Ltd.. Invention is credited to Weitao Chen, Inho Park, Yubo Wang, Xiaojian Yang, Minghui Zhang.
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United States Patent |
10,548,215 |
Yang , et al. |
January 28, 2020 |
Flexible printed circuit, method for fabricating the same, and
display device
Abstract
A flexible printed circuit, a method for fabricating the same,
and a display device are provided. The circuit includes: a
substrate, at least one conductive structure located on the
substrate, a contact electrode group, an encapsulation layer
configured to encapsulate the conductive structure and the contact
electrode group, and a ventilating film. The contact electrode
group includes a first and a second contact electrodes, configured
to be electrically connected respectively with two ends of the
conductive structure; the encapsulation layer and the substrate
constitute a cavity and a liquid storage area communicating with
each other; the conductive structure includes a liquid conductive
substance located in the cavity; and the liquid storage area is
configured to store the liquid conductive substance, and the
ventilating film is configured to encapsulate the liquid storage
area.
Inventors: |
Yang; Xiaojian (Beijing,
CN), Wang; Yubo (Beijing, CN), Zhang;
Minghui (Beijing, CN), Park; Inho (Beijing,
CN), Chen; Weitao (Beijing, CN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Beijing BOE Display Technology Co., Ltd.
BOE Technology Group Co., Ltd. |
Beijing
Beijing |
N/A
N/A |
CN
CN |
|
|
Assignee: |
Beijing BOE Display Technology Co.,
Ltd. (Beijing, CN)
BOE Technology Group Co., Ltd. (Beijing, CN)
|
Family
ID: |
61096257 |
Appl.
No.: |
16/124,896 |
Filed: |
September 7, 2018 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20190132946 A1 |
May 2, 2019 |
|
Foreign Application Priority Data
|
|
|
|
|
Oct 31, 2017 [CN] |
|
|
2017 1 1045588 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
51/0097 (20130101); H05K 1/0272 (20130101); H05K
3/107 (20130101); H05K 3/285 (20130101); H05K
1/09 (20130101); H05K 1/118 (20130101); H01L
51/52 (20130101); H05K 1/028 (20130101); H05K
1/0283 (20130101); H05K 3/4007 (20130101); G02F
1/133305 (20130101); H05K 3/007 (20130101); H05K
1/0393 (20130101); H05K 2201/015 (20130101); H05K
2201/10128 (20130101); Y02E 10/549 (20130101); H05K
2201/09036 (20130101); H05K 1/0277 (20130101); H05K
1/11 (20130101); H05K 2203/166 (20130101) |
Current International
Class: |
H05K
1/02 (20060101); H05K 3/00 (20060101); H05K
1/03 (20060101); H05K 3/10 (20060101); H05K
3/40 (20060101); H05K 3/28 (20060101); H05K
1/11 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Patel; Ishwarbhai B
Attorney, Agent or Firm: Arent Fox LLP Fainberg; Michael
Claims
The invention claimed is:
1. A flexible printed circuit, comprising: a substrate, at least
one conductive structure located on the substrate, at least one
contact electrode group, an encapsulation layer configured to
encapsulate the conductive structure and the contact electrode
group, and a ventilating film, wherein: the contact electrode group
comprises a first contact electrode and a second contact electrode,
configured to be electrically connected respectively with two ends
of the conductive structure; the encapsulation layer and the
substrate constitute a cavity and a liquid storage area
communicating with each other; the conductive structure comprises a
liquid conductive substance located in the cavity; and the liquid
storage area is configured to store the liquid conductive
substance, and the ventilating film is configured to encapsulate
the liquid storage area, and to enable the liquid storage area to
communicate with an ambient atmosphere.
2. The flexible printed circuit according to claim 1, wherein the
liquid storage area is located on an end of the conductive
structure connected with the first contact electrode.
3. The flexible printed circuit according to claim 2, wherein a
positive projection of the first contact electrode and a positive
projection of the liquid storage area on the substrate partially
overlap with each other, and a positive projection of the second
contact electrode and a positive projection of the cavity on the
substrate partially overlap with each other.
4. The flexible printed circuit according to claim 1, wherein the
encapsulation layer comprises a first encapsulation layer and a
second encapsulation layer located on a side of the first
encapsulation layer away from the substrate; and a surface of the
first encapsulation layer away from the substrate is flush with a
surface of the liquid storage area, and a surface of the second
encapsulation layer away from the substrate is flush with a surface
of the ventilating film.
5. The flexible printed circuit according to claim 1, wherein a
part of a surface of the first contact electrode close to the
substrate is exposed; or a part of the surface of the first contact
electrode away from the substrate is exposed; and a part of a
surface of the second contact electrode close to the substrate is
exposed; or a part of the surface of the second contact electrode
away from the substrate is exposed.
6. The flexible printed circuit according to claim 1, wherein a
diameter of an aperture of the ventilating film lies between a
diameter of a largest one of air molecules and a diameter of a
particle of the liquid conductive substance.
7. The flexible printed circuit according to claim 6, wherein the
ventilating film comprises expanded polytetrafluoroethylene.
8. The flexible printed circuit according to claim 1, wherein the
liquid conductive substance comprises liquid metal or electrolyte
solution, and the liquid metal comprises an indium-tin-gallium
alloy material or mercury.
9. The flexible printed circuit according to claim 1, wherein the
substrate comprises a resin material, and the encapsulation layer
comprises the resin material.
10. A display device, comprising the flexible printed circuit
according to claim 1.
11. A method for fabricating the flexible printed circuit according
to claim 1, the method comprising: preparing a substrate; forming
at least one contact electrode group on the substrate; forming an
encapsulation layer in a 3D printing process, wherein a cavity
configured to accommodate a liquid conductive substance, and a
liquid storage area communicating with the cavity are arranged on a
side of the encapsulation layer close to the substrate; injecting
the liquid conductive substance into the liquid storage area to
enable the liquid conductive substance to connect with the contact
electrode group; and encapsulating the liquid storage area using a
ventilating film.
12. A method for fabricating the flexible printed circuit according
to claim 1, the method comprising: preparing a substrate; forming
at least one contact electrode group on the substrate; forming a
conductive layer of liquid metal at temperature below a melting
point of the liquid metal, and patterning the conductive layer,
wherein the conductive layer is connected with the at least one
contact electrode group; forming an encapsulation layer to
encapsulate the conductive layer and the contact electrode group at
temperature below the melting point of the liquid metal to form a
cavity and a liquid storage area of the conductive structure; and
forming a ventilating film to encapsulate the liquid storage
area.
13. A method for fabricating the flexible printed circuit according
to claim 1, the method comprising: preparing a base substrate;
forming an encapsulation layer on the base substrate, wherein a
groove configured to accommodate a liquid conductive substance, and
a liquid storage area communicating with the groove are arranged on
the encapsulation layer, and a ventilating film is arranged on a
side of the liquid storage area close to the base substrate;
filling the liquid conductive substance in the groove and the
liquid storage area on the encapsulation layer; preparing a
substrate; forming at least one contact electrode group on the
substrate; aligning the base substrate with the liquid conductive
substance filled, with the substrate with the contact electrode
group formed; and removing the base substrate.
Description
CROSS-REFERENCES TO RELATED APPLICATIONS
This application claims priority to Chinese patent application No.
201711045588.2 filed on Oct. 31, 2017, which is incorporated herein
by reference in its entirety.
FIELD
The present disclosure relates to the field of display
technologies, and particularly to a flexible printed circuit, a
method for fabricating the same, and a display device.
BACKGROUND
As the display technologies are advancing constantly, display
screens or touch screens have been widely applied in our life, and
particularly a Liquid Crystal Display (LCD) is predominant in the
market due to a small volume, low power consumption, no radiation,
and other advantages thereof. An Organic Light-Emitting Diode
(OLED) display has also been widely applied in the market due to
self-luminescence, a high response speed, a wide angle of view,
high brightness, high saturation, a low weight, a small thickness,
and other advantages thereof.
As the display technologies are advancing rapidly, there is a
demand for a better display mode, display effect, etc., and more
and more users require higher flexibility and tensility, more
wearable displays, etc. However a traditional Flexible Printed
Circuit (FPC) is not stretchable, and a signal line thereof tends
to be broken in use, so a signal may be transmitted abnormally,
thus hindering the display panel from displaying normally, which
would result in display abnormality. Accordingly it is difficult
for the flexible printed circuit in the related art to be
applicable to the tensile display device or wearable device.
SUMMARY
In one aspect, an embodiment of the disclosure provides a flexible
printed circuit including: a substrate, at least one conductive
structure located on the substrate, at least one contact electrode
group, an encapsulation layer configured to encapsulate the
conductive structure and the contact electrode group, and a
ventilating film. The contact electrode group includes a first
contact electrode and a second contact electrode, configured to be
electrically connected respectively with two ends of the conductive
structure; the encapsulation layer and the substrate constitute a
cavity and a liquid storage area communicating with each other; the
conductive structure includes a liquid conductive substance located
in the cavity; the liquid storage area is configured to store the
liquid conductive substance, and the ventilating film is configured
to encapsulate the liquid storage area, and to enable the liquid
storage area to communicate with an ambient atmosphere.
In a possible implementation, in the flexible printed circuit above
according to the embodiment of the disclosure, the liquid storage
area is located on an end of the conductive structure connected
with the first contact electrode.
In a possible implementation, in the flexible printed circuit above
according to the embodiment of the disclosure, a positive
projection of the first contact electrode and a positive projection
of the liquid storage area on the substrate partially overlap with
each other, and a positive projection of the second contact
electrode and a positive projection of the cavity on the substrate
partially overlap with each other.
In a possible implementation, in the flexible printed circuit above
according to the embodiment of the disclosure, the encapsulation
layer includes a first encapsulation layer and a second
encapsulation layer located on the side of the first encapsulation
layer away from the substrate; and a surface of the first
encapsulation layer away from the substrate is flush with a surface
of the liquid storage area, and a surface of the second
encapsulation layer away from the substrate is flush with a surface
of the ventilating film.
In a possible implementation, in the flexible printed circuit above
according to the embodiment of the disclosure, a part of a surface
of the first contact electrode close to the substrate is exposed;
or a part of the surface of the first contact electrode away from
the substrate is exposed; and a part of the surface of the second
contact electrode close to the substrate is exposed; or a part of
the surface of the second contact electrode away from the substrate
is exposed.
In a possible implementation, in the flexible printed circuit above
according to the embodiment of the disclosure, a diameter of an
aperture of the ventilating film lies between a diameter of a
largest one of air molecules and a diameter of a particle of the
liquid conductive substance.
In a possible implementation, in the flexible printed circuit above
according to the embodiment of the disclosure, the ventilating film
includes expanded polytetrafluoroethylene.
In a possible implementation, in the flexible printed circuit above
according to the embodiment of the disclosure, the liquid
conductive substance includes liquid metal or electrolyte solution,
and the liquid metal includes an indium-tin-gallium alloy material
or mercury.
In a possible implementation, in the flexible printed circuit above
according to the embodiment of the disclosure, the substrate
includes a resin material, and the encapsulation layer includes a
resin material.
In another aspect, an embodiment of the disclosure provides a
display device including the flexible printed circuit above.
In still another aspect, an embodiment of the disclosure provides a
method for fabricating the flexible printed circuit above. The
method includes: preparing a substrate; forming at least one
contact electrode group on the substrate; forming an encapsulation
layer in a 3D printing process, wherein a cavity configured to
accommodate a liquid conductive substance, and a liquid storage
area communicating with the cavity are arranged on a side of the
encapsulation layer close to the substrate; injecting the liquid
conductive substance into the liquid storage area to enable the
liquid conductive substance to connect with the contact electrode
group; and encapsulating the liquid storage area using a
ventilating film.
In still another aspect, an embodiment of the disclosure provides a
method for fabricating the flexible printed circuit above. The
method includes preparing a substrate; forming at least one contact
electrode group on the substrate; forming a conductive layer of
liquid metal at temperature below a melting point of the liquid
metal, and patterning the conductive layer, wherein the conductive
layer is connected with the at least one contact electrode group;
forming an encapsulation layer to encapsulate the conductive layer
and the contact electrode group at temperature below the melting
point of the liquid metal to form a cavity and a liquid storage
area of the conductive structure; and forming a ventilating film to
encapsulate the liquid storage area.
In still another aspect, an embodiment of the disclosure provides a
method for fabricating the flexible printed circuit above. The
method includes preparing a base substrate; forming an
encapsulation layer on the base substrate, wherein a groove
configured to accommodate a liquid conductive substance, and a
liquid storage area communicating with the groove are arranged on
the encapsulation layer, and a ventilating film is arranged on a
side of the liquid storage area close to the base substrate;
filling the liquid conductive substance in the groove and the
liquid storage area on the encapsulation layer; preparing a
substrate; forming at least one contact electrode group on the
substrate; aligning the base substrate with the liquid conductive
substance filled, with the substrate with the contact electrode
group formed; and removing the base substrate.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top view of a flexible printed circuit according to an
embodiment of the disclosure;
FIG. 2A and FIG. 2B are schematic sectional views along AB in FIG.
1;
FIG. 3 is a schematic diagram of the flexible printed circuit
according to the embodiment of the disclosure while being
stretched;
FIG. 4 is a schematic diagram of the flexible printed circuit
according to the embodiment of the disclosure after being
stretched;
FIG. 5 is a first flow chart of a method for fabricating the
flexible printed circuit above according to an embodiment of the
disclosure;
FIG. 6A to FIG. 6C, FIG. 8, and FIG. 10A to FIG. 10C are schematic
structural diagrams in the fabricating method above according to
the embodiment of the disclosure;
FIG. 7 is a second flow chart of a method for fabricating the
flexible printed circuit above according to an embodiment of the
disclosure; and
FIG. 9 is a third flow chart of a method for fabricating the
flexible printed circuit above according to an embodiment of the
disclosure.
DETAILED DESCRIPTION
In view of the problem in the related art that a flexible printed
circuit is not stretchable, embodiments of the disclosure provide a
flexible printed circuit, a method for fabricating the same, and a
display device.
Implementations of the flexible printed circuit, the method for
fabricating the same, and the display device according to the
embodiments of the disclosure will be described below in details
with reference to the drawings. The thicknesses and shapes of
respective layers in the drawings are not intended to reflect any
real proportion, but merely intended to illustrate the content of
the disclosure.
In one aspect, an embodiment of the disclosure provides a flexible
printed circuit, and as illustrated in FIG. 1, FIG. 2A, and FIG.
2B, the flexible printed circuit includes: a substrate 11, at least
one conductive structure 12 located on the substrate 11, at least
one contact electrode group 13, an encapsulation layer 14
configured to encapsulate the at least one conductive structure 12
and the at least one contact electrode group 13, and a ventilating
film 15.
The contact electrode group 13 includes a first contact electrode
131 and a second contact electrode 132, configured to be
electrically connected respectively with two ends of the conductive
structure.
The encapsulation layer and the substrate constitute at least one
cavity 21 and at least one liquid storage area 22 communicating
with each other.
The conductive structure 12 includes a liquid conductive substance
located in the cavity 21.
The liquid storage area 22 is configured to store the liquid
conductive substance, and the ventilating film 15 is configured to
encapsulate the liquid storage area 22, and to enable the liquid
storage area 22 to communicate with the ambient atmosphere.
In the flexible printed circuit above according to the embodiment
of the disclosure, the substrate and the encapsulation layer are
generally stretchable, and the conductive structure 12 includes the
liquid conductive substance located in the cavity 21, so while the
flexible printed circuit is being stretched, the liquid conductive
substance in the cavity 21 flows with varying atmospheric pressure,
so that the liquid conductive substance is connected with the first
contact electrode 131 and the second contact electrode 132, thus
enabling the flexible printed circuit to be stretchable while
ensuring the conductivity of the flexible printed circuit.
As illustrated in FIG. 1, in an implementation, the first contact
electrode 131 and the second contact electrode 132 in each contact
electrode group 13 are typically arranged on two ends of the
flexible printed circuit, and a conductive structure 12 is
connected respectively with the first contact electrode 131 and the
second contact electrode 132 located on two tends thereof, so two
components can be connected through the flexible printed circuit.
FIG. 1 illustrates seven conductive structures 12 and seven contact
electrode groups 13 by way of an example, but the embodiment of the
disclosure will not be limited to any specific numbers of
conductive structures 12 and of contact electrode groups 13. In
some embodiments, the first contact electrode 131 and the second
contact electrode 132 generally can be made of a metal material,
and for example, the first contact electrode and the second contact
electrode can be copper electrodes, or the first contact electrode
and the second contact electrode can be made of another conductive
material which can be flexible or rigid. Since the first contact
electrode and the second contact electrode are typically located
respectively on two ends of the flexible printed circuit, a stress
occurring on the flexible printed circuit being stretched cannot be
concentrated on the first contact electrode and the second contact
electrode, so the stretchability of the flexible printed circuit
cannot be affected by the first contact electrode and the second
contact electrode, and the first contact electrode and the second
contact electrode cannot be broken while the flexible printed
circuit is being stretched.
In some embodiments, referring to FIG. 1, since each conductive
structure 12 is connected with the first contact electrode 131 and
the second contact electrode 132 located on two ends of the
conductive structure, two adjacent conductive structures 12 shall
be insulated from each other, so one conductive structure 12
corresponds to one liquid storage area 22. Furthermore in order to
facilitate a fabrication process, several adjacent conductive
structures 12 can share a ventilating film 15, although the
embodiment of the disclosure will not be limited to any specific
number of ventilating films 15 and any specific number of liquid
storage areas 22.
The flexible printed circuit above according to the embodiment of
the disclosure is configured to connect a display screen with a
Printed Circuit Board (PCB) in a display device, and specifically
the flexible printed circuit can be connected respectively with
contact pads on the display screen through the first contact
electrodes (e.g., golden fingers) located on the same end thereof,
and connected respectively with contact pads on the printed circuit
board through the second contact electrodes located on the other
end thereof. Furthermore the flexible printed circuit can also be
applicable to other devices, e.g., a wrist ring, a wrist watch, or
other devices, although the flexible printed circuit will not be
limited to any specific application thereof.
Referring to FIG. 1, FIG. 2A, and FIG. 2B, in the flexible printed
circuit above according to the embodiment of the disclosure, the
substrate and the encapsulation layer can be made of a material
which is stretchable, so the substrate 11 and the encapsulation
layer 14 can be stretchable. The conductive structure 12, which
roles as electric conduction, includes the liquid conductive
substance located in the cavity 21. Since the liquid conductive
substance can flow, the conductive structure 12 cannot be broken
while the flexible printed circuit is being stretched. FIG. 1
merely illustrates the shape of the conductive structure 12 in one
implementation of the embodiment of the disclosure, and the shape
of the conductive structure 12 can be set as needed in reality,
although the embodiment of the disclosure will not be limited
thereto.
Furthermore the liquid storage area 22 is arranged to store the
liquid conductive substance, and the ventilating film 15 is
arranged to encapsulate the liquid storage area 22, and to enable
the liquid storage area 22 to communicate with the ambient
atmosphere, so that the liquid conductive substance can flow to
lower atmospheric pressure while the flexible printed circuit is
being stretched, to thereby maintain good contact of the conductive
structure 12 with the first contact electrode 131 and the second
contact electrode 132 after flexible printed circuit is stretched,
so as to guarantee the conductivity. A specific stretching process
will be described in details with reference to FIG. 3 and FIG.
4.
FIG. 2A and FIG. 2B illustrates the original state of the flexible
printed circuit which is not stretched, and as can be apparent, the
liquid conductive substance in the cavity 21 well contacts with the
first contact electrode 131 and the second contact electrode 132 on
two ends thereof. As illustrated in FIG. 3, while the flexible
printed circuit is being stretched, the volume of the cavity 21 is
increasing, so a negative pressure area is created at the position
denoted by the arrow C as illustrated, that is, the atmospheric
pressure at the arrow C is lower, and the atmospheric pressure in
the liquid storage area 22 communicating with the ambient
atmosphere is higher, so that the liquid conductive substance in
the liquid storage area 22 flows to the negative pressure area C
due to the atmospheric pressure. FIG. 4 illustrates the structure
of the flexible printed circuit after being stretched, where the
liquid conductive substance well contacts with the first contact
electrode 131 and the second contact electrode 132. In a real
application, the contents of the liquid conductive substance in the
cavity 21 and the liquid storage area 22 shall be set according to
the extent to which the flexible printed circuit is stretched, so
that the liquid conductive substance can well contact with the
contact electrode group in both the original state and the
stretched state.
It shall be noted that that in the embodiment of the disclosure,
the liquid conductive substance above can refer to a conductive
substance which is in a liquid state in an operating environment of
the flexible printed circuit, but will not be limited to a
conductive substance which is in a liquid state at room
temperature, and for example, the liquid conductive substance can
be a metal material which is in a liquid state in an operating
environment. Since the liquid metal is characterized in high
electrical conductivity, high thermal conductivity, high
elasticity, high yield strength, etc., and heat-resistance,
erosion-resistance, etc., and does not flow, and is less volatile
and less oxidized at high temperature, the flexible printed circuit
can be provided with good conductivity and high stability. Since
the melting points of the liquid metal of different materials are
different, the liquid metal material to be used shall be determined
as needed in a real operating environment.
In some embodiments, in the flexible printed circuit above
according to the embodiment of the disclosure, as illustrated in
FIG. 2A and FIG. 2B, the liquid storage area 22 is located on the
end of the conductive structure 12 connected with the first contact
electrode 131, so that while the flexible printed circuit is being
stretched, the liquid conductive substance flows in only one
direction, thus facilitating good contact of the liquid conductive
substance with the first contact electrode 131 and the second
contact electrode 132 on two ends thereof; or the liquid storage
area 22 can be arranged on the end of the conductive structure 12
connected with the second contact electrode 132, or the liquid
storage area 22 can be at another position as needed in reality,
although the embodiment of the disclosure will not be limited
thereto.
Referring to FIG. 2A and FIG. 2B again, in the flexible printed
circuit above according to the embodiment of the disclosure, a
positive projection of the first contact electrode 131 and a
positive projection of the liquid storage area 22 on the substrate
partially overlap with each other, and positive projections of the
second contact electrode 132 and the cavity 21 on the substrate
partially overlap with each other. Thus the contact area of the
first contact electrode (or the second contact electrode) with the
liquid conductive substance can be increased, and the conductive
structure 12 cannot be easily disconnected from the first contact
electrode (or the second contact electrode), thus guaranteeing the
conductivity of the flexible printed circuit. By way of an example
in which the positive projections of the second contact electrode
and the cavity on the substrate partially overlap with each other,
there is an overlapping area between the second contact electrode
and the cavity 21 on the right end of the cavity as illustrated in
FIG. 2A and FIG. 2B, so that both the side of the second contact
electrode and the surface of the second contact electrode located
in the cavity 21 can contact with the liquid conductive substance,
thus greatly increasing the contact area as compared with only the
side of the second contact electrode contacting with the liquid
conductive substance. The same principle will apply to the first
contact electrode overlapping with the liquid storage area 22, so a
repeated description thereof will be omitted here.
In some embodiments of the disclosure, in the flexible printed
circuit as illustrated in FIG. 2A and FIG. 2B, the encapsulation
layer 14 can include a first encapsulation layer 141 and a second
encapsulation layer 142, the second encapsulation layer is located
on a side of the first encapsulation layer 141 away from the
substrate 11.
The surface of the first encapsulation layer 141 away from the
substrate is flush with the surface of the liquid storage area 22,
and the surface of the second encapsulation layer 142 away from the
substrate is flush with the surface of the ventilating film 15.
As can be seen from FIG. 2A and FIG. 2B, the first encapsulation
layer 141 is arranged to form the structures of the liquid storage
area 22 and the cavity 21 to accommodate the liquid conductive
substance, and the second encapsulation layer 142 is arranged flush
with the surface of the ventilating film 15 to thereby maintain the
flatness of the surface of the encapsulation layer 14 away from the
substrate 11, thus making the flexible printed circuit more compact
in structure. In a specific implementation, the first encapsulation
layer 141 and the second encapsulation layer 142 can be made of the
same material, or can be made of different materials, and the first
encapsulation layer 141 and the second encapsulation layer 142 can
be formed separately, or can be formed in an integral structure in
the same process. In the embodiment of the disclosure, the surface
of the first encapsulation layer away from the substrate is flush
with the surface of the liquid storage area, and the surface of the
second encapsulation layer away from the substrate is flush with
the surface of the ventilating film in one implementation of the
embodiment of the disclosure, but in a real application, the
surface of the first encapsulation layer away from the substrate
may alternatively be not flush with the surface of the liquid
storage area, and the surface of the second encapsulation layer
away from the substrate may alternatively be not flush with the
surface of the ventilating film.
In some embodiments, in the flexible printed circuit above, a part
of the surface of the first contact electrode close to the
substrate 11 is exposed as illustrated in FIG. 2A, and the largest
width of the encapsulation layer 14 can be set larger than the
width of the substrate 11 so that the side of the first contact
electrode 131 away from the conductive structure 12 is flush with
the encapsulation layer 14 to thereby expose a part of the surface
of the first contact electrode 131 close to the substrate 11; or a
part of the surface of the first contact electrode 131 away from
the substrate 11 is exposed as illustrated in FIG. 2B, and the
width of the substrate 11 can be set larger than the largest width
of the encapsulation layer 14 so that the side of the first contact
electrode 131 away from the conductive structure 12 is flush with
the substrate 11 to thereby expose a part of the surface of the
first contact electrode 131 away from the substrate 11. Alike a
part of the surface of the second contact electrode close to the
substrate can be exposed, or a part of the surface of the second
contact electrode away from the substrate can be exposed. In this
way, on one hand, the first contact electrode (or the second
contact electrode) can be electrically connected with the liquid
conductive substance sealed between the substrate and the
encapsulation layer, and on the other hand, the exposed part of the
surface of the first contact electrode (or the second contact
electrode) can be connected with another component, e.g., a contact
pad on the display screen.
In some embodiments, in order to enable the liquid storage area 22
to communicate with the atmosphere, and to avoid the liquid metal
in the liquid storage area 22 from flowing out of the ventilating
film 15, in the flexible printed circuit above, the diameter of an
aperture of the ventilating film 15 lies between the diameter of
the largest one of air molecules and the diameter of a particle of
the liquid conductive substance. In some embodiments, the
ventilating film 15 above includes expanded
polytetrafluoroethylene.
In a real application, the liquid conductive substance above is a
substance which is in a liquid state in an operating environment of
the flexible printed circuit, so the material of the liquid
conductive substance can be set as needed in a real operating
environment. Since an operating environment of a mobile phone, a TV
set, a computer, or another display device is typically at room
temperature, and may be below zero centigrade in some special case,
the liquid conductive substance may be a material with a low
melting point, and for example, the liquid conductive substance may
include an indium-tin-gallium alloy material with a melting point
of approximately -19.quadrature., and a bolting point of
approximately 1300.quadrature., that is, the indium-tin-gallium
alloy is in a liquid state at temperature above -19.quadrature.,
and the indium-tin-gallium alloy material is relatively stable, so
it can operate in a normal operating environment. Specifically the
proportion of the respective elements in the indium-tin-gallium
alloy material can be Ga:In:Sn=68.5%:21.5%:10%. Furthermore the
liquid conductive substance can alternatively be electrolyte
solution or mercury, or can be another material which can operate
in a normal operating environment, although the embodiment of the
disclosure will not be limited thereto.
In the flexible printed circuit in some embodiments of the
disclosure, the substrate 11 includes a resin material, and the
encapsulation layer 14 includes a resin material. Specifically both
the first encapsulation layer 141 and the second encapsulation
layer 142 in the encapsulation layer 14 can be made of a resin
material. Since the resin material has some elasticity, it can
enable the flexible printed circuit to be stretchable. In some
embodiments, the resin material above is elastic resin, or can be
made of another material with a good stretch effect, although the
embodiment of the disclosure will not be limited to any specific
materials of the substrate 11 and the encapsulation layer 14.
In another aspect, based upon the same inventive idea, an
embodiment of the disclosure further provides a display device
including the flexible printed circuit above. The display device
can be applicable to a mobile phone, a tablet computer, a TV set, a
monitor, a notebook computer, a digital photo frame, a navigator,
or any other product or component with a display function. Since
the display device addresses the problem under a similar principle
to the flexible printed circuit above, reference can be made to the
implementation of the flexible printed circuit above for an
implementation of the display device, and a repeated description
thereof will be omitted here.
In still another aspect, based upon the same inventive idea, an
embodiment of the disclosure further provides a method for
fabricating the flexible printed circuit above. Since the
fabricating method addresses the problem under a similar principle
to the flexible printed circuit above, reference can be made to the
implementation of the flexible printed circuit above for an
implementation of the fabricating method, and a repeated
description thereof will be omitted here.
As illustrated in FIG. 5, a method for fabricating the flexible
printed circuit above according to an embodiment of the disclosure
can include the following steps.
The step S201 is to prepare a substrate 11, e.g., a substrate 11
made of an elastic resin so that the resulting substrate is
stretchable, or a substrate 11 made of another material, although
the embodiment of the disclosure will not be limited to any
specific material of the substrate 11.
The step S202 is to form at least one contact electrode group on
the substrate 11, where as illustrated in FIG. 6A, the contact
electrode group includes a first contact electrode and a second
contact electrode located on two ends of the substrate 11, and the
first contact electrode and the second contact electrode extend
outward relative to the substrate 11 so that parts of the surfaces
of the first contact electrode and the second contact electrode
close to the substrate 11 are exposed, or if parts of the surfaces
of the first contact electrode and the second contact electrode to
be formed away from the substrate 11 are exposed, then the sides of
the first contact electrode and the second contact electrode may be
arranged flush with the side of the substrate 11.
The step S203 is to form an encapsulation layer 14 by a 3D printing
process, where the side of the encapsulation layer 14 close to the
substrate 11 is arranged with a cavity 21 configured to accommodate
a liquid conductive substance, and a liquid storage area 22
communicating with the cavity 21, as illustrated in FIG. 6B. For
example, the encapsulation layer 14 can be made of elastic resin so
that the encapsulation layer is stretchable, or the encapsulation
layer 14 can be made of another material, although the embodiment
of the disclosure will not be limited to any specific material of
the encapsulation layer 14; and in the 3D printing process, the
encapsulation layer 14 can be formed integrally, or the first
encapsulation layer 141 and the second encapsulation layer 142 can
be formed separately.
The step S204 is to inject the liquid conductive substance into the
liquid storage area 22 to enable the liquid conductive substance to
connect with the contact electrode group, as illustrated in FIG.
6C. In a real application, the content of the liquid conductive
substance to be injected into the liquid storage area 22 shall be
determined according to the extent to which the flexible printed
circuit is stretched, to ensure that the liquid conductive
substance can well contact with the contact electrode group in both
an original state and a stretched state.
The step S205 is to encapsulate the liquid storage area 22 using a
ventilating film 15, thus resulting in the structure as illustrated
in FIG. 2A.
In still another aspect, based upon the same inventive idea, an
embodiment of the disclosure further provides a method for
fabricating the flexible printed circuit above. Since the
fabricating method addresses the problem under a similar principle
to the flexible printed circuit above, reference can be made to the
implementation of the flexible printed circuit above for an
implementation of the fabricating method, and a repeated
description thereof will be omitted here.
As illustrated in FIG. 7, a method for fabricating the flexible
printed circuit above according to an embodiment of the disclosure
can include the following steps.
The step S301 is to prepare a substrate 11, e.g., a substrate 11
made of elastic resin, or a substrate 11 made of another material,
although the embodiment of the disclosure will not be limited to
any specific material of the substrate 11.
The step S302 is to form at least one contact electrode group on
the substrate 11, where as illustrated in FIG. 6A, the contact
electrode group includes a first contact electrode and a second
contact electrode located on two ends of the substrate 11, and the
first contact electrode (or the second contact electrode) extends
outward relative to the substrate 11 so that a parts of the surface
the first contact electrode (or the second contact electrode) close
to the substrate 11 is exposed, or if a part of the surface of the
first contact electrode (or the second contact electrode) to be
formed away from the substrate 11 is exposed, then the side of the
first contact electrode (or the second contact electrode) may be
arranged flush with the side of the substrate 11.
The step S303 is to form a conductive layer 16 of liquid metal at
temperature below a melting point of the liquid metal, and to
pattern the conductive layer 16, where the conductive layer 16 is
connected with the at least one contact electrode group. The liquid
metal is in a solid state at the temperature below the melting
point of the liquid metal, so the conductive layer 16 can be formed
in a solid state, and patterned into the structure as illustrated
in FIG. 8.
The step S304 is to form an encapsulation layer 14 at temperature
below the melting point of the liquid metal for encapsulating the
conductive layer 16 and the contact electrode group to form a
cavity 21 and a liquid storage area 22 of a conductive structure
12, as illustrated in FIG. 6C. The conductive layer 16 is still in
a solid state at the temperature below the melting point of the
liquid metal, and the encapsulation layer 14 is formed on the
conductive layer 16 and the contact electrode group to thereby form
the cavity 21 and the liquid storage area 22 of the conductive
structure 12 as illustrated in FIG. 6C; and the conductive layer 16
is in a liquid state at temperature above the melting point of the
liquid metal, and thus can flow in the formed cavity 21 and liquid
storage area 22.
The step S305 is to form a ventilating film 15 to encapsulate the
liquid storage area 22, thus resulting in the structure as
illustrated in FIG. 2A.
In still another aspect, based upon the same inventive idea, an
embodiment of the disclosure further provides a method for
fabricating the flexible printed circuit above. Since the
fabricating method addresses the problem under a similar principle
to the flexible printed circuit above, reference can be made to the
implementation of the flexible printed circuit above for an
implementation of the fabricating method, and a repeated
description thereof will be omitted here.
As illustrated in FIG. 9, a method for fabricating the flexible
printed circuit above according to an embodiment of the disclosure
can include the following steps.
The step S401 is to prepare a base substrate 17, where the base
substrate 17 can be a stretchable base substrate 17, or a base
substrate 17 which is not stretchable, e.g., a glass substrate,
although the embodiment of the disclosure will not be limited to
any specific material of the base substrate 17.
The step S402 is to form an encapsulation layer 14 on the base
substrate 17, as illustrated in FIG. 10A, where a groove 18
configured to accommodate a liquid conductive substance, and a
liquid storage area 22 communicating with the groove 18 are
arranged on the encapsulation layer 14, and a ventilating film 15
is arranged on the side of the liquid storage area 22 close to the
base substrate 17. In the fabricating method according to this
embodiment, the encapsulation layer 14 is formed on the base
substrate 17, and then patterned to form the groove 18 (i.e., the
encapsulated cavity 21) and the liquid storage area 22 configured
to accommodate the liquid conductive substance, and specifically
the encapsulation layer can be formed in an integral structure in
one patterning process, or a pattern of a first encapsulation layer
141, and a pattern of a second encapsulation layer 142 can be
formed separately in two patterning processes to form a pattern of
the encapsulation layer 14.
The step S403 is to fill the liquid conductive substance in the
groove 18 and the liquid storage area 22 on the encapsulation layer
14, as illustrated in FIG. 10B. In a real application, the content
of the liquid conductive substance to be injected into the liquid
storage area 22 shall be determined according to the extent to
which the flexible printed circuit is stretched, so that the liquid
conductive substance can well contact with the contact electrode
group in both an original state and a stretched state.
The step S404 is to prepare a substrate 11, e.g., a substrate 11
made of elastic resin so that the substrate is stretchable, or a
substrate 11 made of another material, although the embodiment of
the disclosure will not be limited to any specific material of the
substrate 11.
The step S405 is to form at least one contact electrode group on
the substrate 11. As illustrated in FIG. 6A, the contact electrode
group includes a first contact electrode and a second contact
electrode located on two ends of the substrate 11, and the first
contact electrode (or the second contact electrode) extends outward
relative to the substrate 11 so that a parts of the surface the
first contact electrode (or the second contact electrode) close to
the substrate 11 is exposed, or if a part of the surface of the
first contact electrode (or the second contact electrode) to be
formed away from the substrate 11 is exposed, then the side of the
first contact electrode (or the second contact electrode) may be
arranged flush with the side of the substrate 11.
The step S406 is to align the base substrate 17 with the liquid
conductive substance filled, with the substrate 11 with the contact
electrode group formed, that is after the base substrate 17 is
aligned with the substrate 11, they are bonded using adhesive or in
another fixing mode, as illustrated in FIG. 10C.
The step S407 is to remove the base substrate 17, thus resulting in
the structure as illustrated in FIG. 2A.
In this embodiment, firstly the encapsulation layer 14 is formed
upside down, and the liquid conductive substance is filled, and
thereafter the encapsulation layer is aligned with the substrate 11
with the contact electrode group formed, and the flexible printed
circuit after they are aligned is placed upside down, thus
resulting in the structure as illustrated in FIG. 2A.
In the flexible printed circuit, the method for fabricating the
same, and the display device according to the embodiments of the
disclosure, the conductive structure includes the liquid conductive
substance located in the cavity, so while the flexible printed
circuit is being stretched, the liquid conductive substance in the
cavity flows with varying atmospheric pressure, so that the liquid
conductive substance is connected with the first contact electrode
and the second contact electrode, thus enabling the flexible
printed circuit to be stretchable while being conductive.
Evidently those skilled in the art can make various modifications
and variations to the disclosure without departing from the spirit
and scope of the disclosure. Thus the disclosure is also intended
to encompass these modifications and variations thereto so long as
the modifications and variations come into the scope of the claims
appended to the disclosure and their equivalents.
* * * * *